[ On Thursday, June 28, 2001 at 13:41:55 (-0400), Fletcher E Kittredge wrote: ]
Subject: Re: Cable Modem [really responsible engineering]
I haven't been able to figure your statement above out. I thought you were saying that given a client device MAC address, one could determine which cable modem MAC address was servicing that client MAC, even in the cases where the cable modem was just acting as a bridge.
Luckily not much of this thread has been polluting NANOG, so I'm not 100% sure what your goal is here, but I will point out that: The client-IP addresses active on any CPE interface of any cable modem compliant with the DOCS-CABLE-DEVICE-MIB (rfc2669) can easily be discovered with SNMP. From there it's very simple to find the client MAC in your dhcpd.leases file (though I don't know why the IP#s wouldn't be sufficient for most needs). Note too that this same table should also act as a filter to lock static addresses to a given modem if its entries are assigned by the operator. The only problem of course is that you've got to SNMP-scan all your modems to find which customer's using a given IP# (I did that a couple of times just this morning! ;-). There are no doubt ways to cache this information, and maybe even refresh a cache intelligently. There may even be a better, proprietary, way do do such searches in well implemented head-end systems (doesn't seem to be in Terayon's though). -- Greg A. Woods +1 416 218-0098 VE3TCP <gwoods@acm.org> <woods@robohack.ca> Planix, Inc. <woods@planix.com>; Secrets of the Weird <woods@weird.com>